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Some Delphi unit testing notes

Posted by jpluimers on 2019/03/21

A few notes I wrote down when coaching a team to write better unit tests and test tooling form themselves.

  • unit tests test a unit of code
  • integrating tests test multiple units of code, which can go as far as having external dependencies
  • mocks simulate depencencies
  • unit tests are being executed by a unit test runner
  • you can group tests into test suites, which can contain other suites, and determine order of tests (which can be important for integration tests).
  • unit tests and suites register them to be eligible for running (a test without an encompassing suite presents itself as a suit with one test)
  • the runner optionally has a mechanism to filter the eligible suites and tests down to the ones actually being run

References:

In the particular case for this team, testing was mostly done using DUnit for Delphi.

Here, these are worth mentioning:

  • The configuration is not limited to the GuiTestRunner: any DUnit based test runner can use it (though the default console TextTestRunner skips it, but https://github.com/graemeg/fptest/blob/master/src/TextTestRunner.pas and https://github.com/VSoftTechnologies/DUnit-XML/blob/master/Example/DUnitXMLTest.dpr shows how it can be used).
    • It comes down to either Suite.LoadConfiguration(IniFileName, UseRegistry, True) or RegisteredTests.LoadConfiguration(IniFileName, UseRegistry, True) where
      • IniFileName contains the INI filename, for instance from ExtractFilePath(ParamStr(0)) + 'dunit.ini' or from a ParamStr parameter on the command-line.
      • UseRegistry usually is False
  • If you want to disable all exceptions for easier debugging, but still want to catch failures, then you can enable Break on Failures (see screenshot below) so breaking tests will throw an EBreakingTestFailure.
  • Registration
    • Per test or per suite
    • You do not need a ITestSuite implementing class in order to register a suite (just pass a SuitePath when registering multiple tests)
    • Basically the only reasons for having a ITestSuite implementing class (like descending from TTestSuite) are
      • to have a specific SetUp or TearDown for that suite level
      • to allow \ backslash or / forward slash in test suite names (which is unwise because a lot of tooling sees those as suite hierarchy separators)
    • function TestSuite(AName: string; const Tests: array of ITest): ITestSuite;
    • procedure RegisterTest(SuitePath: string; test: ITest); overload;
    • procedure RegisterTest(test: ITest); overload;
    • procedure RegisterTests(SuitePath: string; const Tests: array of ITest); overload;
    • procedure RegisterTests(const Tests: array of ITest); overload;
    • function RegisteredTests: ITestSuite;
  • Configuration is exclusion based
    • procedure TTestSuite.LoadConfiguration(const iniFile: TCustomIniFile; const section: string);
    • procedure TTestSuite.SaveConfiguration(const iniFile: TCustomIniFile; const section: string);
    • The configuration file default name is DUnit.ini
    • The DUnit.ini file will be saved after the GUI tests are run (overwriting any changes) when the Auto Save Configuration is enabled (which is the default)
    • All tests are configured in
      • sections
        • named (of course inside [] brackets) as Tests.TestPath, where TestPath either
          • is the name of the test class
          • is a . period separated path of suites ending in an test class
        • values having keys named either
          • the test method with a value 0 to disable the test
          • a test method followed by .RunCount with an integer value indicating how often that test needs to be executed
        • note that with either TestName=1 or TestName.RunCount=1 will disappear from the ini file because those are default values
      • There are no values to indicate tests need to be run (so by default registered tests eligible to be run are being run)
    • An example file (without .RunCount ) is at [WayBack] delphidicontainer/dunit.ini at master · danieleteti/delphidicontainer · GitHub
    • You can add comments to INI files using a semi colon at the start of the line; see [WayBack] Do standard windows .ini files allow comments? – Stack Overflow

Registration and exclusion are two separate concerns.

To configure non-GUI tests, first run the GUI tester, configure it, then copy the resulting DUnit.ini file to the environment where the non-GUI tests are being run.

Be sure to check out test decorators, and maybe amend them with dependency injection. Example for apply database setup/teardown to a full suite of tests: [WayBack] How to organize testing of DB in dUnit — IT daily blog, news, magazine, technologies

Some resurrected documentation links because not all links from [WayBack] DUnit – Xtreme testing for Delphi and [WayBack] DUNIT: An Xtreme testing framework for Delphi programs succeed.

–jeroen

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